Techniques and Training with GreenLight HPS 120-W Laser Therapy of the Prostate: Position Paper

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1 european urology supplements 7 (2008) available at journal homepage: Techniques and Training with GreenLight HPS 120-W Laser Therapy of the Prostate: Position Paper Gordon Muir a, Fernando Gómez Sancha b, *, Alexander Bachmann c, Benjamin Choi d, Edward Collins e, Jean de la Rosette f, Oliver Reich g, Shahin Tabatabaei h, Henry Woo i a Department of Urology, King s College Hospital, London, UK b Institute of Advanced Urological Surgery, Madrid, Spain c Department of Urology, University Hospital, Basel, Switzerland d Department of Urology, Weill Medical College of Cornell University, Ithaca, New York, USA e California Urological Services, San Francisco, California, USA f Department of Urology, Academic Medical Center, University of Amsterdam, The Netherlands g Department of Urology, Ludwig-Maximilians-University, Munich, Germany h Department of Urology, Massachusetts General Hospital, Boston, Massachusetts, USA i Department of Urology, Westmead Hospital, The University of Sydney, Australia Article info Keywords: GreenLight HPS laser Photoselective vaporization of the prostate Benign prostatic hyperplasia Technique Training Abstract We report the technical recommendations of the International Green- Light User Group on photoselective vaporization of the prostate in men with benign prostatic hyperplasia using the GreenLight HPS system (American Medical Systems, Minnetonka, Minnesota, USA). This highpower system employs a 120-W laser, which is a modification of the previous 80-W potassium-titanyl-phosphate (KTP) laser. The objective of this report is to optimize the efficacy and safety of the procedure by drawing on the experience of this multicentre international group. In this regard, recommendations for training are made, which relate to existing users of the 80-W KTP laser as well as to new laser users. # 2007 European Association of Urology. Published by Elsevier B.V. All rights reserved. * Corresponding author. Institute of Advanced Urological Surgery, Paseo de la Castellana 23, Madrid, Spain. Tel ; Fax: address: fernando@icua.es (F. Gómez Sancha). 1. Introduction Photoselective vaporization of the prostate (PVP) using the 80-W potassium-titanyl-phosphate (KTP) 532-nm laser is a recent technological development in the use of lasers as an alternative to transurethral resection of the prostate (TURP) for the treatment of symptomatic benign prostatic hyperplasia. Originally introduced by Malek et al. in 1998 utilizing a 60-W KTP laser, a subsequent pilot study of PVP with the 80-W KTP laser showed a good outcome and minimal side effects in men with prostate volumes of ml [1]. PVP works on a different mechanism than the existing holmium laser enucleation of the prostate, in that it involves prostate tissue ablation through vaporization as opposed to enucleation /$ see front matter # 2007 European Association of Urology. Published by Elsevier B.V. All rights reserved. doi: /j.eursup

2 european urology supplements 7 (2008) Further progress with PVP has been the introduction of the high-performance system (HPS) 120-W laser, which aims to reduce lasing time and improve clinical outcomes while maintaining the same degree of safety for patients. Technical recommendations on the GreenLight 80-W KTP laser (American Medical Systems, Minnetonka, Minnesota, USA) have been published by the International GreenLight User Group, in addition to training recommendations [2]. In this paper, we discuss how the technique is used with the GreenLight HPS 120-W laser system and what the new training requirements will be. 2. General principles Several factors have to be considered when using the GreenLight HPS 120-W laser. The new HPS system operates with a fibre that emits a beam that is more collimated and more powerful than the Fig. 1 Working distance of 120-W fibre from the cystoscope: (a) at a distance where there is more perspective and orientation is better; (b) close to the cystoscope, where there is a higher risk of telescope damage and orientation is worse. Fig. 2 Photoselective vaporization of the prostate. The fibre should be rotated in a sweeping fashion with rotation amplitude reduced to an arc of 608 (c). This avoids an increase in the distance from the fibre to the tissue, which would produce an oblique light footprint, reduce vaporization efficiency, increase reflection of light, and increase coagulation (a, b). 80-W KTP laser. This translates in vitro as well as clinically into faster vaporization and a greater ability to penetrate prostate tissue from longer fibre distances. The increase in vaporization speed is associated with faster bubble generation and more tissue debris, which has the potential to reduce the working visibility. For this reason, it is helpful to work with the fibre slightly further from the cystoscope, which also reduces the risk of damage to the cystoscope from reflected energy. This also translates into better orientation inside the prostatic fossa during surgery (Fig. 1). With this technique, it is important that the surgeon is sure that he/she is firing inside the prostatic fossa and not in the bladder. Caution is recommended at the actual bladder neck, where the fibre should be kept closer to the cystoscope and the tissue to avoid damage to the ureteral orifices. When handling the actual fibre during lasing, with the increased 120-W power it is important to move the fibre slowly but constantly to avoid drilling holes in the prostate tissue, and spreading the energy in this way will create a smooth surface. In addition, the rotation speed of the fibre must be adapted to the efficiency of vaporization: if efficiency is high, rotation can be speeded up, whereas if efficiency is low due to poor vascularization of a region, rotation should be slowed down. The rotation angle of the fibre must be kept small (ie, from 5 to 7 o clock, or 608) to keep the angle of incidence of the beam as perpendicular to the tissue as possible (Fig. 2). The working distance of the laser from the tissue is a key issue. In vitro studies have shown that it is possible to work slightly further away with the 120-W laser compared with the 80-W laser, at up to 4 mm, and still obtain good vaporization (Fig. 3). However, a more efficient

3 372 european urology supplements 7 (2008) Fig. 3 Efficiency of vaporization at different working distances for the 80-W KTP laser and the 120-W HPS lasers based on in vitro studies with canine prostate tissue. Based on data supplied by W. Kang (American Medical Systems Research Group). clinical vaporization effect is seen working at shorter distances in near contact mode. It is possible that at greater tissue distances the beam interferes more with debris and bubbles arising from the tissue, thus compromising vaporization efficiency. As with the 80-W laser recommendations, it is important to avoid direct contact with the tissue as excessive heat reflection will char and damage the fibre. Gentle fingertip movements of the laser fibre and cystoscope are recommended, and the approach must be rather more static than the movements employed with TURP. This approach will minimize bleeding and improve the chances of completing the procedure with a small-calibre cystoscope, with reduced irrigation efficiency and without bleeding. One can also choose to move the fibre in association with the cystoscope when lasing, or the cystoscope can remain static while the fibre is moved. The latter option can minimize friction to the prostatic and urethral surfaces, again reducing the likelihood of bleeding (Fig. 4). Space restraints within the prostate may require starting the procedure at the lower power of 80 W with rapid fibre movement to avoid tissue contact until a working channel has been created and then switching to the 120-W power. This will also reduce the likelihood of damaging the fibre through excess contact at 120 W. With experience, it may be possible to use the 120-W power from start to finish even in small prostates, but novice users and PVP users without experience with the 120-W laser should lower the power to 60 or 80 W initially. Expert users of the 120-W laser should aim to have only minimal, very short pauses during a lasing session. Another novel concept is fibre navigation, that is, the use of the fibre to navigate around the prostatic fossa Fig. 4 Relationship of the cystoscope and the laser fibre: (a) moving the whole cystoscope to go from point A to B while keeping the fibre and cystoscope in close proximity can result in friction; (b) moving the fibre from point A to B while keeping the cystoscope static can minimize trauma to the gland. # IGLU Group. with a continuous beam operating at the correct working distance. Spreading the energy inside the cavity in a symmetrical fashion as opposed to the sequential approach (ie, middle lobe, then right lobe, and then left lobe) with a TURP is analogous to peeling back layer after layer of prostate tissue. Another important distinction compared with some other lasing systems is the type of cavity being aimed for with the HPS, which should be a wine-glass or TURP-like shape, as opposed to a small cylindrical channel. 3. The modular approach to photoselective vaporization of the prostate The initial stages of patient evaluation, preparation, and anaesthesia as well as detailed approaches to vaporizing the prostate have been described previously [2]. Given here are the basic principles for the HPS procedure, which can be divided into six modules.

4 european urology supplements 7 (2008) Fig. 5 Schematic showing the modular approach to vaporization of the prostate with the GreenLight HPS laser. (a) Introduction of the cystoscope: (i) always look at the anterior urethra (the beak is not visible), (ii) trying to see the whole lumen of the urethra risks damaging it. (b) Careful cystoscopy is conducted to visualize the ureteral orifices and rule out bladder tumours; if the middle lobe is large, then pushing down on it may cause bleeding. (c) Creation of the working space: (i) the anterior start, (ii) central spiral technique, (iii) posterior start. (d) Clearance of the lateral lobes: (i) midline to lateral direction, (ii) descending direction, (iii) ascending direction. (e) The apex: (i) endoscopic view showing the solitary veru montanum, (ii) lateral view. (f) The middle lobe can be approached in several ways: (i) progressive flattening using the laser in a rotating fashion around and aiming towards the centre of the middle lobe to avoid damaging the ureteral orifices, (ii) sideways lasering, (iii) lasering at the base to enucleate and extract a small middle lobe. (g) The bladder neck: (i) there is still a step down to the trigone; if the urethral orifices are not seen, then a midline incision is made to the circular fibres,

5 374 european urology supplements 7 (2008) (ii) urethral orifices are now revealed, (iii) if the urethral orifices are visible, a bilateral incision opens the bladder neck, (iv) bladder neck still elevated after removal of middle lobe. (h) Final steps: check that no major lumps protrude into the lumen, no bleeders remain, and the cavity remains open when the bladder is empty. # IGLU Group Preliminary cystoscopy It is essential to introduce the cystoscope carefully, using either an optical obturator that smoothes the cystoscope s beak or by tilting the cystoscope towards the 6 o clock position to avoid the beak causing urethral or prostatic damage (Fig. 5a, b). Cystoscopy generates information on prostate size, length of the prostatic urethra, the presence of a urethral stricture and allows the ureteral orifices and the bladder neck to be localized. The cystoscope must not be moved in and out unnecessarily, as this is likely to cause bleeding; scratching of the prostatic surface should also be avoided for the same reason. With large prostates or large middle lobes, it may be very difficult to perform a cystoscopy without causing bleeding, which might compromise visibility during the subsequent operation. In such cases, it may be more appropriate to rule out the presence of any bladder tumours (if clinically relevant) using flexible cystoscopy before surgery. Any congenital abnormalities at the trigone (eg, ectopic ureters or duplex systems) should also be ruled out at this stage Creation of the working space Creating a working space at the start of the procedure is imperative, because it allows the fibre to move more easily, thus avoiding contact with tissue and consequent fibre degradation (Fig. 5c). This space will provide good orientation during

6 european urology supplements 7 (2008) surgery and also permit optimal irrigation during lasing, which is important for visibility. The continuous flow cystoscope through which the laser fibre is inserted can become obstructed with tissue particles, so it is important to check that irrigation is working and that there is no pooling of irrigant or bladder distension. If particles do obstruct the flow, lasing should cease and the fibre carrier detached from the outer sheath to allow the obstructing particles to flow out. The use of a continuous flow pump can help regulate the flow and pressure of irrigation, thus permitting high flow with limited pressure. Pressure can be increased when needed, such as to improve visibility during bleeding. The objective is to maintain a filled but not over distended bladder during surgery. There are several approaches to generating the working channel, including anterior, central spiral, and posterolateral. The anterior approach aims to reduce the chances of bleeding due to friction of the cystoscope on the prostatic urethral mucosa in large prostates. The central approach is probably easier for beginners working on small prostates. The posterolateral approach can be performed respecting the bladder neck or middle lobe, or start by vaporizing them down to the circular fibres at the bladder neck. At the end of this module, there should be two perfectly defined landmarks: the bladder neck (ie, the transition between coagulated tissue at the bladder neck and bladder mucosa) and the lower limit of vaporization (ie, the transition between coagulated tissue of the prostatic mucosa and the urethral sphincteric mucosa at the level of the veru montanum) Lateral lobes With two clearly defined landmarks, the bladder neck and the urethral sphincter, this phase of the operation allows for safe and fast vaporization of tissue within those limits with minimal breaks in lasing (Fig. 5d). The lateral lobes are lasered in a symmetrical manner, layer by layer, with the objective to obtain a smooth surface. This can be achieved if the laser is fired selectively against peaks of tissue on the surface (the mountains), flattening them out, instead of targeting areas already vaporized (the valleys). One added benefit of the smooth surface is that it is much easier to control any bleeds that may occur than if the surface were irregular. The objective of this module should be to achieve a concave surface on each side, with as complete a removal of lateral tissue as possible, as this will facilitate further operative steps Apex Lasing at the apex should be very precise in order to clear carefully the apical tissue and to avoid damage to the sphincter (Fig. 5e). The objective is for complete vaporization of paracollicular tissue. Care should be taken with anterior vaporization at the level of the veru montanum; working with the fibre far from the cystoscope allows for anterior vaporization without rotating the cystoscope. Special care must be exerted here to avoid sphincter damage, as the beak of the cystoscope can maintain an open sphincter when the cystoscope is withdrawn and compromise the sphincter localization. At the end of this stage, all apical tissue should have been removed and the lonely veru appearance achieved Bladder neck/middle lobe The bladder neck and middle lobe can be left to the end of the procedure, because it is much easier and safer to vaporize the middle lobe once the lateral lobes have been cleared (Fig. 5f, g). The first objective should be to flatten the middle lobe. This can be accomplished by firing left to right or right to left, or better, by progressively smoothening its contour, making sure that the beam is directed at the centre of the middle lobe, thus avoiding the ureteral orifices. With difficult middle lobes, experienced users might find it easier to detach a small middle lobe and push it into the bladder at this stage, but it must be small enough to allow its extraction with a large Zero-tip 1 stone basket. Enucleation of large middle lobes is not recommended. Once the middle lobe has been flattened, the bladder neck might still be elevated. At this stage, a bilateral bladder neck incision (5 and 7 o clock) down to the circular fibres delineates the desired depth of vaporization. If the ureteral orifices are not visualized, it might be safer to first perform a midline 6 o clock incision until they are seen. The tissue between the incisions is vaporized until an unobstructed view of the trigone is achieved Completion It is important to empty the bladder to check if bumps of obstructing tissue protrude into the collapsed prostatic fossa (Fig. 5h). Any remaining bleeders should be identified and dealt with. A digital rectal examination can also help to identify remaining tissue in the posterolateral area. At completion there should be visible a wide, open, concave cavity with a smooth surface (Fig. 6).

7 376 european urology supplements 7 (2008) Training recommendations Fig. 6 The final cystoscope image of the apex following laser vaporization of the prostate. The energy usage per unit volume of prostate gland can be determined at the end of the procedure Fig. 7. illustrates the typical energy usage according to prostate volume for a new user of the 120-W GreenLight HPS laser. It should be noted that the total energy delivered does not seem to be associated with dysuria per se, but instead it is a symptom of excessive coagulation. With the 120-W laser and the collimated beam, vaporization is more efficient and there is no excess coagulation working at longer distances of 1 3 mm, so there is less chance of dysuria than with the 80-W laser and the divergent fibre. We believe that, in principle, it is better to obtain a wine-glass-shaped cavity using more energy than to carve a small channel in the prostate due to the unfounded fear of producing dysuria. The training recommendations with the 120-W HPS laser are dependent on whether the user is an experienced or inexperienced PVP user. For the experienced PVP user, one who has completed 30 cases, mentoring and proctoring should take place on at least one occasion. The inexperienced PVP user who is a trained urologist should undertake a formal training course, watch several live procedures performed by an experienced surgeon, and be subsequently proctored for a minimum of two cases, although this number can vary at the proctor s discretion. Any ongoing training should be conducted with the aid of the proctor. There is a perceived need for an international board of certified proctors, and this is critical for establishing a high standard of excellence for this procedure. We recommend that objective assessment milestones be established, as shown in Table 1. Twenty cases are required to be completed before an objective assessment can be carried out. These early cases should involve prostates sized ml (assessed using TRUS), with a preference for smaller prostates. These patients should not be in retention or on anticoagulants or have prostates with large middle lobes. Experience should be gained on the use of video endoscopy, as this is the principle visual system under which the laser operates. The recommended stepwise process for lasing is creating a working channel, then vaporizing the lateral lobes, apex, and middle lobe and bladder neck. We look forward to the availability of computerized simulators under development that could greatly aid learning, but the use of a wet lab, preferably one run by the manufacturer with certification, is an option until simulators are available. One possible future development is official certification for training in conjunction with one of the urological associations, Table 1 Objective assessment milestones in the training programme for the HPS laser Fig. 7 Energy usage with the GreenLight HPS 120-W laser according to preoperative prostate volume. Knowledge of anatomy laser physics laser-tissue interactions steps of the operation Handling of probe and cystoscope Management of bleeding Management of complications Management of damage to the ureteral orifices Catheter management Management of postoperative complications

8 european urology supplements 7 (2008) such as the European Association of Urology or the American Urological Association. Conflicts of interest All authors have received honoraria from AMS for meeting attendance and the following authors act as paid consultants for AMS: J. de la Rosette, B. Choi, E. Collins and S. Tabatabaei. AMS have also provided limited research funding for G. Muir. References [1] Hai MA, Malek RS. Photoselective vaporization of the prostate: initial experience with a new 80 W KTP laser for the treatment of benign prostatic hyperplasia. J Endourol 2003;17:93 6. [2] Gómez Sancha F, Bachmann A, Choi BB, Tabatabaei S, Muir GH. Photoselective vaporization of the prostate (Green- Light PV): lessons learnt after 3500 procedures. Prostate Cancer Prostatic Dis 2007;10: